Generally, to cope with a danger of air pollution and petroleum depletion, related technologies for an eco-friendly vehicle using electric energy as power of the vehicle has been actively developed. The eco-friendly vehicle includes a hybrid electric vehicle, a fuel cell electric vehicle, and an electric vehicle.
The eco-friendly vehicle includes a high voltage battery for driving the vehicle and a low voltage battery for driving an electric sub assembly or an electronic sub assembly. The electric energy charged in the high voltage battery is used as a power source for the vehicle and the electric energy charged in the low voltage battery is used as power for the electric sub assembly or the electronic sub assembly (ESA) of the vehicle.
Meanwhile, a plurality of electric sub assemblies or electronic sub assemblies mounted in the eco-friendly vehicle may include combined parts of substrates configured of elements, such as electrical parts, electronic parts and resistors or capacitors, which are supplied with power from a battery for the vehicle, with mechanical tools. To meet a development of a vehicle-related technology and needs of a driver, the number of electric sub assemblies or electronic sub assemblies mounted in the vehicle tends to increase and a magnitude of voltage required as power in each of the electric sub assemblies or electronic sub assemblies has gradually diversified.
A vehicle in accordance with the related art includes a plurality of low voltage battery power converters to provide power required for various types of electric sub assemblies or electronic sub assemblies, thereby outputting voltages corresponding to each power supply for the electric sub assemblies or the electronic sub assemblies.
FIG. 1 is a block diagram illustrating a plurality of low voltage DC-DC converter of the vehicle in accordance with the related art. Referring to FIG. 1, a plurality of low voltage DC-DC converters 110 and 210 of an eco-friendly vehicle in accordance with the related art each include a 12V output low voltage DC-DC converter 110 and a 48V output low voltage DC-DC converter 120 for outputting a first voltage (for example, 48V) and a second voltage (for example, 12V) which are voltages required in a plurality of electric sub assemblies or electronic sub assemblies mounted in a vehicle.
The 12V output low voltage DC-DC converter 110 is supplied with DC power of a high voltage from the high voltage battery 100 mounted in the eco-friendly vehicle and reduces the supplied DC power of the high voltage to be converted into DC power of a 12V low voltage, thereby supplying the DC power of the 12V low voltage as power for the electric sub assembly using 12V and power for charging the low voltage battery. The high voltage battery 100 includes a plurality of battery cells formed therein and outputs power of a high voltage of several hundred volts such as about 270V or higher as a total output voltage of each of the battery cells.
The 12V output low voltage DC-DC converter 110 includes an AC voltage converting unit 111, a transformer 112, a rectifying unit 113, an LC filter unit 114, and a 12V output unit 115.
The AC voltage converting unit 111 is supplied with DC power of a high voltage from the high voltage battery and converts the supplied DC power of the high voltage into AC power of a high voltage having a desired pulse width by a full bridge type of pulse width modulation (PWM).
The transformer 112 performs insulating and stepping-down functions. The AC power of the high voltage input from the AC voltage converting unit 111 is transferred from a primary side coil to a secondary side coil, in which the primary side coil and the secondary side coil are mounted in the transformer 112 and are insulated from each other. Further, the AC power of the high voltage input from the AC voltage converting unit 111 is reduced to the AC power of the 12V low voltage depending on a turn ratio of the transformer 112.
The rectifying unit 113 again converts 12V AC power input from the transformer 112 into 12V DC power by an operation of a plurality of mounted rectifying diodes.
Since the 12V DC power input from the rectifying unit 113 has a pulse width converted by the AC voltage converting unit 111, the LC filter unit 114 removes a ripple by an operation of the mounted LC filter to convert the 12V DC power into 12V DC power in a smooth state, not a pulse type.
The 12V output unit 115 is supplied with the 12V DC power in the smooth state from the LC filter unit 114 to be provided as power for charging a plurality of electric sub assemblies or electronic sub assemblies using the 12V DC power and a low voltage battery.
In components which configure the 48V output low voltage DC-DC converter 120, functions of an AC voltage converting unit 121, a rectifying unit 123, and an LC filter unit 124 which are the rest components other than the components configuring the 48V output low voltage DC-DC converter 110 and a transformer 122 and a first voltage (48V) output unit 125 are the same as those of the AC voltage converting unit 111, the rectifying unit 113, and the LC filter unit 114. Therefore, the detailed description of the components performing the same functions is omitted and the transformer 122 and the 48V output unit 125 which are different components will be described in detail.
The 48V output low voltage DC-DC converter 120 includes the AC voltage converting unit 121, the transformer 122, the rectifying unit 123, the LC filter unit 124, and the first voltage (48V) output unit 125.
The transformer 122 performs insulating and stepping-down functions. The AC power of the high voltage input from the AC voltage converting unit 121 is transferred from a primary side coil to a secondary side coil, in which the primary side coil and the secondary side coil are mounted in the transformer 122 and are insulated from each other. Further, the AC power of the high voltage input from the AC voltage converting unit 111 is reduced to the AC power of the 48V low voltage depending on a turn ratio of the transformer 112.
The 48V output unit 125 is supplied with the 48V DC power in the smooth state from the LC filter unit 124 and provides the input 48V DC power as power for the plurality of electric sub assemblies or electronic sub assemblies which use the 48V DC power.
Meanwhile, due to the increase in an electric field load of the eco-friendly vehicle, a capacity of the 12V output low voltage DC converter 110 is continuously increased. The increase in the 12V electric field load means the increase in current in the fixed voltage and a size of an electric field power cable is also increased. This adversely affects fuel efficiency, size, and performance of the eco-friendly vehicle. To solve the above problems, the electric sub assemblies or electronic sub assemblies using the 48V power have been developed and applied. However, to supply the power required for the 48V electric field load, in addition to the foregoing 12V output low voltage DC converter 110, the 48V output low voltage DC converter 120 needs to be mounted in the eco-friendly vehicle. This is a cause of increasing a size and manufacturing costs of the eco-friendly vehicle.
The plurality of low voltage power converter mounted in the vehicle occupies a predetermined space in a limited space of the vehicle and when any one of the plurality of low voltage power converters is broken, there is a need to confirm whether all the low voltage power converters mounted in the vehicle are broken. Therefore, a need exists for a technology of a voltage-power converter which may provide a multi-voltage output to be able to provide different power required for the electric sub assemblies or the electronic sub assemblies of the vehicle.